Thomas Aquinas, on Ps 28:3

“The voice of the Lord is upon the waters; the God of majesty hath thundered, The Lord is upon many waters.”

“Mystically, "The voice of the Lord upon the waters." A twofold benefit is implied: namely, of conversion and of the gifts that are given to the converted. "The voice of the Lord in power." According to the mystery, this can be explained in two ways. In one way, so that it is referred to the preaching of Christ; and so it deals with the conversion of Jews and Gentiles. Of the Jews, when he says "upon the waters." Human beings are likened to waters, because just as waters, people flow and do not return, 2 Kgs. 14. Hence "upon the waters" is said "the voice," that is, the preaching of the Lord, that is, upon the Jewish people, because from the teaching of God -- not yet incarnate, but awaited -- the Jews were converted to God. Concerning the conversion of the Gentiles, it follows when he says, "The God of majesty thundered." Thunder is formed in a cloud, in which the incarnation itself is signified, which is like a cloud: Is. 19: "Behold, the Lord ascends upon a light cloud." The God of majesty, therefore, thundered, that is, the almighty thundered through preaching from the cloud of his flesh: Job 37: "He will thunder with his voice marvelously." And he says "upon many waters," because the voice of the incarnate Lord was not only upon the Jews but upon the Gentiles: Is. 49: "I have given you as a light to the nations," etc. Or "upon the waters" of Baptism; hence from the time that Christ was baptized, this Psalm is sung.”

Imported from an open dataset — not yet checked against the printed edition.